Variations of nutrient elements and its effect on ecological environment off the Changjiang estuarine waters

On the basis of the data obtained in two cruises during October 1997 and May 1998,the concentration distribution and the variation of present species of nutrient elements in the water masses are described.The transform mechanism of present species of nutrients and role of differmt water masses,frontal area and thermohaline transition layer on convergence or divergence and the biogeochemical cycle of nutrient elements off the Changjiang Estuary are studied.Meanwhile,the environmental capacityof nutrients is primarily estimated:they are 1.803×10⁴t DIN and 6.18×10²t PO₄^3--P in autumn,and 4.20×10²t PO₄^3--p in spring.